EP2030952A1 - Method for biologically treating waste waters and recycling sludge - Google Patents

Abstract

The invention relates to a method for biological wastewater treatment and sludge utilization, the sorption and oxidation of wastewater in biocenosis of activated sludge, wastewater aeration and treatment by means of cavitation, a separation of purified water, a catching swollen sludge, a water purification by flocculation, a return of flooded mud for the primary aeration phase and a removal and removal of the worn out precipitate. The degree of purification and the degree of harmlessness of the deposited impurities is increased by carrying out the sorption and oxidation at an atmospheric oxygen saturation of at least 18-22 mg / l, which is generated at least twice in upflow and outflow in three aeration basins with inserted biocenosis Whirling is also carried out, the post-cleaning, the separation and the catching of the mud is carried out in two to three steps, that the mud and the mud particles are divided into two parts, which are treated differently in two cycles, that during the period of this Procedures the wastewater supply to the aeration basins blocked and carried out a multiple circulation-based ventilation and cavitation treatment and that compacted in the sedimentation of the sludge and the enzyme-enriched digester water in the primary stage of the water treatment be returned.

Description

The invention relates to a method for biological wastewater treatment and sludge utilization according to the preamble of claim 1.

• eine Abwasserklärung mittels Biozönose in den Belebtschlammanlagen,
• eine Wassernachreinigung und
• eine Abscheidung von angeschwollenem Schlamm und schwebenden Feststoffen,
• eine Regenerierung von angeschwollenem Schlamm während des biologischen Klärungsvorgangs (sie erfolgt auf der Tragfläche, welche im Abscheider liegt und bei einer Wasserbegasung in Zirkulationsräumen verschleimt. Die Zirkulationsräume befinden sich dabei zwischen den Schichten der Verschleimung),
• einer Rückführung des regenerierten Schlamms in die Belüftungsbecken und
• einer Schlammausräumung (Patent der RF Nr. 2180895 C 02 F3/06, veröff. am 27.03.2002).

A method for biological sewage treatment is known, which includes the following steps:

• a sewage treatment by means of biocenosis in the activated sludge plants,
• a water after-cleaning and
• a separation of swollen sludge and suspended solids,
• a regeneration of swollen sludge during the biological clarification process (it takes place on the support surface, which lies in the separator and in the case of a water aeration, becomes entangled in circulation spaces, the circulation spaces being between the layers of the mucilage),
• a return of the regenerated sludge in the aeration tanks and
• a sludge removal (patent RF No. 2180895 C 02 F3 / 06, publish on 27.03.2002).

This method does not ensure the required degree of cleaning with heavily oxidizable contaminants. It also requires compliance with complicated hydrodynamic behavior in order to maintain the efficiency of the activated sludge in the circulation spaces. In addition, the generated precipitate requires additional treatment for its detoxification.

• eine Abwassersorption und -Oxidation in Biozönose des Belebtschlammes unter Abwasserbegasung;
• eine Kavitationsbehandlung mit geringer Intensität,
• eine Reinwasserabscheidung,
• eine Retention von angeschwollenem Schlamm und
• eine Wassernachreinigung mittels Ausflockung anhand von Verschleimung und Schwerkraftabscheidung, welche in einem Abscheider erfolgen,
• eine Rückführung von angeschwollenem Schlamm in den Sammelbehälter zur Belüftung und
• eine Schlammausräumung.

The closest prior art in terms of the technical result obtained and to the essential feature is a method for biological wastewater treatment (Patent No. RF. 2255905, c 02 F 3/00, publish 10.07.2005). This method includes:

• a sewage sorption and oxidation in biocenosis of the activated sludge under waste gas fumigation;
• a low intensity cavitation treatment,
• a pure water separation,
• a retention of swollen mud and
• a water purification by means of flocculation on the basis of admixture and gravitational separation, which take place in a separator,
• a return of swollen sludge in the sump for ventilation and
• a sludge removal.

The aeration is carried out at least twice: once as pre-aeration and afterwards during the cleaning with an atmospheric oxygen saturation of at least 15 - 20 mg / l.

This process makes it possible to simplify all the equipment used because a feed line is used for such operations as sorption and oxidation.

However, the wastewater treatment requires a fairly large pipeline expansion to such a degree of pollution, which allows the discharge of waste water into the natural waters. However, that is not always feasible. In addition, the deposited impurities can not be rendered harmless enough and require further treatment in order to be subsequently utilized.

The method is not effective enough in the presence of heavily oxidizable contaminants.

It is an object of the invention to increase the degree of purification and the degree of harmlessness of the deposited impurities, so that the separated sludge can be used as a useful product. The further task is the cost reduction in the sewage treatment and the sludge utilization.

The stated object is solved by the features of claim 1.

The result of the proposed technical solution is to increase the degree of water purification, to reduce the cost of cleaning and to increase the degree of harmlessness of the collected pollutants so that the recycled sludge can be used as an organomineral product for various economic applications such as soil improvement and soil fertility enhancement.

• eine Sorption und Oxidation von Abwasser in Biozönose des Belebtschlammes,
• eine Abwasserbelüftung und -behandlung mittels Kavitationsverfahrens mit niedrigem Intensitätsgrad,
• eine Abscheidung von gereinigtem Wasser,
• ein Auffangen von angeschwollenem Schlamm
• eine Wassernachreinigung mittels Ausflockung anhand von Verschleimung und Schwerkraftabscheidung,
• eine Rückführung von angeschwollenem Schlamm zur primären Belüftungsphase und
• eine Entnahme und Entfernung des abgenutzten Niederschlages.

The technical result mentioned is achieved in the following way. The known method for biological wastewater treatment and sludge utilization comprises the following process steps:

• a sorption and oxidation of wastewater in biocenosis of activated sludge,
• a waste water aeration and treatment by means of a low-intensity cavitation method,
• a separation of purified water,
• a catch of swollen mud
• a water purification by means of flocculation on the basis of mucus and gravity separation,
• a return of swollen sludge to the primary ventilation phase and
• a removal and removal of the worn down precipitate.

The wastewater aeration is carried out at least twice. The first aeration takes place until the atmospheric oxygen saturation level of at least 15 - 20 mg / l is reached. Later, further ventilation can be done. The catching of the swollen sludge and the slurrying takes place in a separator with a defined load, which has the mucus. This known method is characterized by the following features:

The sorption and oxidation of waste water in the biocenosis of the activated sludge are combined with the sorption and oxidation process by means of the mucilage at an atmospheric oxygen saturation of at least 18 - 22 mg / l.

This process is consistently carried out in three phases. All phases are carried out in separate aeration tanks.

The aeration tanks differ from each other due to the used biocenosis of the activated sludge and the mucilage. The mixing of the Activated sludge with the wastewater to be clarified in each aeration basin at least twice in the inflow and outflow. The inflow and outflow is generated in the aeration basin by means of a turbulence of the water-air mixture. The water-air mixture is produced during the treatment according to the cavitation method with a low degree of intensity and the ventilation, which is carried out in each phase of the process.

The post-cleaning, the separation of purified water and the capture of swollen sludge and mucus particles is consistently in two to three steps. The collected precipitate consists of the swollen mud and the mucus particles. The precipitation is divided. Each of the parts is conveyed to one of the aeration basins where the water purification was previously carried out. A part is used for the regeneration of the mud. The rest is used for the treatment of the mud.

In the treatment of the recovered precipitate, its recovery is carried out with the high and low intensity cavitation treatment in at least two cycles.

The waste water feed into each of the aeration basins used to regenerate swollen sludge or for precipitation treatment is blocked for a period of time required for such operations.

During these operations, a multiple circulation-based ventilation and cavitation treatment is performed.

Thereafter, the sludge is compacted in the settling process. The enzyme-enriched digester water (muddy water) in the precipitation treatment process is returned to the primary stage of the water clarification process.

The increase in the degree of water purification is achieved by combining the sorption and oxidation process of the wastewater in the biocenosis of the activated sludge with the sorption and oxidation process by means of the mucilage. These processes are carried out consistently in three stages, which are characterized by the biocenosis used in each stage differ. Each of the biocenoses differs from the one previously used in that each has a broader composition of the types of microorganisms. These microorganisms have the ability to process difficultly oxidizable contaminants. This assumes that there is no oxygen deficiency during cleaning. Therefore, the oxygen concentration in the water-sludge mixture of about 18 - 22 mg / l is maintained. This makes it possible to significantly expand the biodiversity of the activated sludge and the mucilage and to supply the biocenosis with the oxygen content required for its normal function.

This oxygen content, in turn, is achieved during sorption and oxidation by introducing atmospheric oxygen into the effluent treated by the low intensity cavitation process. This plastic water-air mixture is promoted in the lower part of the aeration basin. This minimizes the pressure drop losses. It is also achieved a uniform oxygen concentration in the upflow.

The procedure is carried out as follows:

The coarse mechanical impurities are removed from the wastewater. This wastewater is directed into the sump of the pump station. Then the wastewater is pumped by the pumps for pre-cleaning. In the pre-treatment, the water is treated by the low-intensity cavitation method. This contributes to the growth of germs in the water to be purified. The basic cleaning is carried out consistently in three stages, namely in three separate aeration tanks. This is where sorption and oxidation occur in the biocenosis of the activated sludge and in the mucilage. The biological mucus is attached to the net carriers.

Each of the purification stages is distinguished by the particular biocenosis of the activated sludge used and the biologically active slime attached to the net carriers.

During treatment, the water circulates through each aeration tank at least twice, depending on the level of water contamination. The highest possible oxygen saturation of the water-sludge mixture in the aeration tanks is achieved by means of its supply of the plastic water-air mixture during the recirculation into the lower part of the aeration basin. The plastic water-air mixture is produced by treating the water during its pumping by the low-intensity cavitation method. This mixture is supplemented with atmospheric oxygen.

The mixing of the activated sludge with the water to be purified takes place consistently in the upflow and outflow by means of the swirling of this flow. That is, the flow is controllably deflected in the aeration basin circumference.

The water treatment is carried out at an oxygen concentration in the air-sludge mixture of 18 - 22 mg / l. In the aeration basin, conditions are created under which the water-mud stream first flows around the outside of the aeration basin (i.e., its ascending branch). Then it flows down the central area of the aeration basin (descending branch) and the mucus passes, which is attached to the net carriers.

The ascending flow branches are enriched with oxygen more than the descending ones. This provides the opportunity for the nitrification and denitrification processes to occur sequentially. In these processes, the biocenosis first absorbs the oxygen from the water-air mixture and then uses it to oxidize the contaminants. This achieves the high degree of cleaning.

The biocenosis used in each of the aeration tanks was formed after the stepwise removal of impurities (from the light to the difficult to oxidize). This removal takes place by means of an uninterrupted cultivation of the respective species stock of the microorganisms in the aeration basin.

In the first stage of biological purification, the readily oxidizable organics of the activated sludge are removed. The biocenosis of this activated sludge is characterized by a relatively low stock of species containing 5-7 groups of microorganisms. In the second stage of the biocenosis in the aeration basin, the additional arithmetic increase from the next 8-10 microorganism groups to the already existing ones is observed. For the specified cleaning operation The microorganisms from the two previous stages in the third aeration basin are supplemented by new types of microorganisms, namely by 12-14 groups thereof. Thus, the removal of impurities from the water to be purified takes place gradually. First, the easily oxidizable, then the medium oxidizable and then the hard-to-oxidize contaminants are removed.

After all three aeration tanks have passed, the mixture of sewage and swollen sludge enters the separator. Here, the separation of the pure water and the interception of the swollen sludge occur. This is also the final purification by flocculation on the basis of mucilage and gravity separation. At the same time, the oxygen saturation of the water-sludge mixture decreases, although it still remains fairly high (10 -15 mg / l). This completes the deep water purification. The actual separation of the activated sludge from the water to be purified takes place gradually in the separators. In the first stage, the heaviest flakes of activated sludge and in the next stages the light flakes are deposited. The settling process of the activated sludge biomass and the mucilage is that a certain ratio of the amount of incoming biomass to the number of settling stages is selected. The more biomass, the more stages for weaning. However, the number of stages must be at least two, because in the first stage, the separation of suspended solids of up to 10 - 15 mg / l in pure water is achieved. In the second stage, the separation of suspended matter up to 2 - 4 mg / l is ensured. The sewage water is then forwarded for detoxification, and the sludge mixture deposited in the separator bottom is conveyed to the first aeration tank for regeneration. As soon as the high degree of regeneration (volume) has been reached, part of it is passed on to the third aeration basin for further treatment and utilization in order to obtain a useful product.

Regeneration of the swollen sludge occurs during recirculation at maximum atmospheric oxygen saturation and during low-intensity cavitation treatment. In the course of regeneration the swollen mud regains its working activity.

In the treatment of excess sludge intended for recovery, the multiple recirculation-assisted aeration and cavitation treatment of sludge is performed. In this case, the cavitation treatment with low and high intensity level takes place alternately for sludge poisoning. During this cavitation treatment, the shells of the microorganisms are destroyed. Their ferments are released, which contribute to the intensive enrichment with biologically active substances. The biologically active substances support the function of the living microflora of the current stabilization reactor. These resources are promoted along with septic tank water to the initial stage of treatment of the water to be purified.

Once the process of precipitation treatment is completed, the circulation is stopped to condense the precipitate and to separate the septic tank water (overflow water).

The wastewater feed into each of the designated aeration tanks is blocked for the required period of treatment of the swollen sludge to be regenerated and the sludge part to be recycled.

The sludge mixture of the collected organic pollutants, the excess sludge and the moisture of 98% moisture in the amount of 1200 m ³ is processed in the course of 6 hours. The conclusion of this The process is characterized by the minimal amount of dehydrogenase activity (DAI). The sludge mixture is very saturated with air. Therefore, it floats and is compressed, so that the mixture circumference is reduced by three times. The moisture also decreases from 98% to 94%. Since the sludge water has a high specific gravity, it can be deposited well above the lowermost drains. It flows back to the initial stage of cleaning the polluted water. And the compacted treated sludge mixture in the amount of 260 m ³ comes to the other dewatering stages (centrifuging, press-filtering).

example 1

The wastewater freed of coarse mechanical impurities is conveyed into the sump of the pumping station in the amount of 1000 m ³ with the following degree of contamination:

BOD ₂₀ 314 mg / l, COD 562 mg / l, suspended solids 286 mg / l (Table 1).

Thereafter, the wastewater is pumped by means of pre-purification stage. Here the water is treated according to the cavitation method with a low degree of intensity with the cavitation number G = 0.004. The basic cleaning phase is carried out consistently in three stages, namely in separate aeration tanks. Here the sorption and the oxidation in the biocenosis of the activated sludge as well as in the mucilage occur, which is attached to the net carriers.

Each of the purification stages is characterized by the used biocenosis of the activated sludge and by the slime, which is attached to the net carriers.

The first stage of biological purification carried out in the first aeration basin is characterized by the following species population of microorganism groups: Achromobacter, Alcaligenes, Gordonia, Microtrix, Fusdarium, Aquaeductum, Bodo globosus. In the second stage they are supplemented in the aeration basin by the following groups of microorganisms: Sphaerotilus natans, Beggiatoa alba, Acinetobacter, Vorticella convallaria, Zoogloeo ramigera, Opercularia, Flavobacterium, Carchesium, Rotifera, Micrococcus, Bodo edax. In the third aeration basin the new groups of microorganisms are added to the previous microorganisms: Nitrobabacter, Geotrichum, Thiotrix, Pseudomanas, Nematosporangium, Epistylis, Philodina, Monostila, Nitrosomonas, Vorticella microstoma, etc.

The mixing of the activated sludge with the water to be purified takes place consistently in each of the aeration tanks in upflow and outflow. The water-mud stream first flows around the outside of the aeration basin (its ascending branch), then flows down over the middle part of the aeration basin (descending branch) and passes through the slime attached to the net carriers.

In the course of treatment, the water in each aeration basin runs twice. The oxygen saturation of the water-sludge mixture increases (see Table 1), which makes 19, 20.5 and 21.5 mg / l.

Thereafter, the mixture of sewage and swollen sludge comes into the separator. Here, the separation of the pure water and the interception of the swollen sludge, as well as the subsequent purification by flocculation under Use of biologically active slime and gravity separation. The oxygen saturation level of the water-sludge mixture in the first separator drops to 15.9 mg / l, and in the second separator to 13.9 mg / l. After the first separator, the amount of suspended matter in the water to be purified is 15-16 mg / l. The second stage ensures the suspended solids content in the water to be purified of 2.8 mg / l. The pure water is discharged with the impurity concentration to BOD ₂₀ - 3.2 and after COD - 26 mg / L from the device. The sludge mixture deposited in the lower part of the separators is divided. 10 - 15% of it is continuously fed to the first aeration tank for regeneration. The remainder is used to treat the recovered precipitate in the third aeration basin. The degree of purification of wastewater corresponds to the basic parameters: BOD, COD, suspended solids.

The regeneration of the swollen sludge takes place in the first aeration tank during the double recirculation at an atmospheric oxygen saturation up to the concentration of 20.5 mg / l and during the treatment according to the cavitation method with a low intensity degree with the cavitation number G = 0.002. During regeneration, the swollen mud regains its working activity.

When treating the excess sludge fraction intended for recovery, a triple recirculation is carried out with aeration to an air oxygen saturation level of about 18.5 mg / l. The cavitation treatment with low (at cavitation number G = 0.001) and high (cavitation number G = 6.5) intensity level is alternated with sludge poisoning. The sludge mixture in an amount of 1200 m ³ and with a humidity of 98% becomes within 6 Hours processed in the third aeration basin. The process lasts until the minimum size for the Dehydrogenaseaktivkät is reached in the mud mixture. After settling within 4 hours, the sludge mixture floats and is compacted. As a result, the volume of the mixture decreases threefold, and the humidity falls from 98% to 94%. The muddy water can be easily separated and flows back to the beginning of the sewage treatment. The compacted and treated sludge mixture in the amount of 260 m ³ comes in the other dewatering stages (centrifuging). The treated precipitate contains no pathogenic microflora, has no unpleasant odor and is a crumb structure. The content of organic matter is 61%. The proportion of heavy metal salts is present in a harmless bound natural state in the form of complexones.

Examples 1 to 3 for carrying out the method are given in Tables 1 and 2. Table 1 describes the process of water purification in the aeration tanks and separators. Table 2 serves as a continuation of Table 1, indicating the flow parameters associated with the regeneration of the swollen sludge and the recovery of the collected precipitate.

The method makes it possible to increase the degree of water purification and to improve the safety level of the deposited impurities, so that the separated sludge can be used as a useful product. The process also makes it possible to reduce the costs of pure water and precipitation utilization.

Claims (1)

Method for biological wastewater treatment and sludge utilization, comprising the following steps: sorption and oxidation of wastewater in biocenosis of the activated sludge; wastewater aeration and treatment by means of a low-intensity cavitation process, separation of purified water, capture of swollen sludge, flooding of water by flocculation by means of slurring and gravity separation, recirculation of swollen sludge primary aeration phase and removal and removal of worn precipitate, with aeration being performed at least twice until an oxygen saturation level of at least 15-20 mg / l is reached, and wherein swollen sludge collection and sludging take place in a fixed load separator, which includes the mucilage, characterized, that the sorption and the oxidation of the effluents in the biocenosis of the activated sludge are combined with the sorption and oxidation process by means of the slurrying at an atmospheric oxygen saturation of at least 18 - 22 mg / l, that this process is consistently carried out in three stages, whereby three separate aeration tanks are used and the aeration basins differ by the used biocenosis of the activated sludge and the mucilage, that in this case the mixing of the activated sludge with the wastewater to be clarified is carried out in each aeration basin at least twice in the upflow and outflow, that the upflow and outflow in the aeration basin is generated by means of turbulence of the water-air mixture, that the water-air mixture is generated during the treatment according to the cavitation method with a low degree of intensity and at the ventilation made in each phase of the process, that the subsequent cleaning, the deposition of purified water and the collection of mud and swollen Schleimteilchen is performed consistently in two or three steps, with the collected precipitate consists of the swollen sludge and Schleimteilchen, that the precipitate is divided, with each of the parts being conveyed into one of the aeration basins where the water purification was previously carried out, that a part is used for the regeneration of sludge, that the rest is used for the treatment of the mud, that, in the treatment of the waste to be recovered, its recovery is carried out with the high and low intensity cavitation treatment in at least two cycles, that the wastewater feed into each of the aeration basins used for the regeneration of swollen sludge or for the precipitation treatment is thereby blocked for the period of time required for such processes, that during these operations a multiple circulation-based ventilation and cavitation treatment is carried out, that the sludge is then compressed in the settling process and that the enzyme-enriched digester water (muddy water) in the precipitation treatment process is returned to the primary stage of the water clarification process.